The battery technology behind the wheel
Kurt Kelty
Tesla Motors
HETHEL, UKEU SalesGlider Manufacture
TAIPEI, TAIWANMotor Manufacture
SAN CARLOS, CACorporate HQBattery Manufacture
AUBURN HILLS, MIEngineering Office
STORESLos Angeles, CAMenlo Park, CA
In Process:New York, NYMiami, FLSeattle, WAChicago, ILWashington, D.C.Munich, GermanyLondon, UKMonacoZurich, Switzerland
Founded in 2003
>350 employees
2 stores opened, 9 morestores planned for 2009
FACILITIES
LOS ANGELES, CAStyling Studio
Best-in-Class – The 2008 Roadster
Zero-emissions electric powertrain
0-60 mph acceleration: 3.9s
Quarter mile acceleration: 12.7s
EPA driving range: 244 miles
Carbon fiber body, aluminum chassis
Full Federal Motor Vehicle Safety Standards (FMVSS) compliant
2009 model price:– US: $109,000 (Base model)
– EU: €99,000 (Special Signature Edition)
– UK: £82,000 (excluding VAT)
Industry Leading EV Powertrain
Controls and Software
Power Electronics Module
(DC-AC Inverter, Charger)
Proprietary53 kWh Lithium Ion
Battery Pack
Proprietary 250hp AC Induction Motor and
Gearbox
Manufacturing Strategy
HETHEL, UKGlider Manufacture
TAIPEI, TAIWANMotor Manufacture
BAY AREAFinal AssemblyBattery Pack AssemblyPowertrain Integration
Tesla RoadsterGlider in UK; Final assembly in Menlo Park, CA
Key Components
Tesla’s proprietary technology has several key components
BATTERY
Battery Pack: 6,831 cells53 kWhBattery system safetyBattery system durabilityWorldwide approval for transport and usePampered battery environment
MOTOR
Proprietary, 3-phase motor design with copper rotor
87% average efficiency over operating range
Max torque available instantly from start; 14,000 rpm redline
200 kW 3-phase IGBT-based bi-directional inverter
Integral 70-amp 120V/240V charging circuitry
Approx. 3.5 hours for normal charging (Roadster battery)
POWER ELECTRONICS MODULE
Fully integrated vehicle and powertrain control system
Digital motor control
Charge control
Battery state of charge, state of heath and balancing monitoring; battery pack control
CONTROLS AND SOFTWARE
Detail follows
Battery Development Detail
SHEET
Sheet: 621 CellsModular, scalable designIP in charge balancing and coolingBattery longevity (cycle & calendar life)
CELLS
Lithium ion cellsBuilt IP around 18650 form factorInternal cell evaluation labLeverage industry battery chemistry investments
BATTERY
Battery Pack: 6,831 cells53 kWhBattery system safetyBattery system durabilityScalable, automated assemblyWorldwide approval for transport and use
Roadster Battery Pack
Total 18650 cells: 6831
Usable Energy Storage: 53 kWh
Capacity: 150Ah
Total weight 450 kg
Energy Density 120 Wh/kg
Continuous output: 53kW
Nominal OCV 366 volts– (297V min, 411V max)
Auxiliary power available 12 volts@ 200 ampsNormal charge time 3-5 hours
Battery Production
Tesla Approach to Battery Safety/Reliability
1. Start with a safe, reliable cell
2. Prevent thermal runaway
3. Prevent propagation of thermal runaway
4. Redundant monitoring & protection
5. Physically protect the battery pack
6. Extensive testing and validation
Must Meet UL 1642
“Standard for Lithium Ion Batteries”
1. Start with a safe, reliable cell: Li-ion 18650
Internal PTC element in every cell
CID device in every cell
High-temperature separator shutdown
Pressure vent
Dimensionally stable steel case
ARC measures cell internal heat release at high temperatures, giving an indication of thermal stability under failure
1. Start with a safe, reliable cell:Accelerating Rate Calorimeter (ARC) Test Results
3 mm diameter steel nail
1. Start with a safe, reliable cell: Nail Penetration Test
1. Start with a safe, reliable cell:Impact Test
Characterize cells
Perform Vibration Test
USABC Battery Test Procedures Manual, Procedure #10 - Battery Vibration Test / SAEJ2380
The vibration envelopes of this procedure correspond to approximately 100 000 miles of usage at the 90th percentile.
Re-characterize cells
1. Start with a safe, reliable cell:Single cell vibration testing
1. Start with a safe, reliable cellFinal cell selection
Battery cell vendors chosen based on:
– Safety performance in Tesla tests
– Reputation: safety & reliability
– Experience and capacity
• Billions of cells produced to date
– Quality:
• automated production
• controlled environment
– Reasonable price
Tesla Approach to Battery Safety/Reliability
1. Start with a safe, reliable cell
2. Prevent thermal runaway
3. Prevent propagation of thermal runaway
4. Redundant monitoring & protection
5. Physically protect the battery pack
6. Extensive testing and validation
Tesla Approach to Battery Safety/Reliability
1. Start with a safe, reliable cell
2. Prevent thermal runaway
3. Prevent propagation of thermal runaway
4. Redundant monitoring & protection
5. Physically protect the battery pack
6. Extensive testing and validation
Assume any cell will spontaneously go into thermal runaway– passive & active safety features to prevent propagation
– passive systems alone prevent propagation
confirmed in repeated tests
3. Prevent propagation of thermal runaway
0 500 1000 15000
100
200
300
400
500
600
700
800Cell 0Cell 1Cell 2Cell 3Cell 4Cell 5Cell 6Cell 7
3. Prevent propagation of thermal runaway
Tesla Approach to Battery Safety/Reliability
1. Start with a safe, reliable cell
2. Prevent thermal runaway
3. Prevent propagation of thermal runaway
4. Redundant monitoring & protection
5. Physically protect the battery pack
6. Extensive testing and validation
4. Redundant monitoring & protection
Battery pack sensors– Multiple temperature sensors
– Accelerometer
– Tilt sensor
– Humidity sensor
– Immersion sensor
– Under/Over voltage
– Over current
Leads to appropriate safety
response such as contactors opening
Tesla Approach to Battery Safety/Reliability
1. Start with a safe, reliable cell
2. Prevent thermal runaway
3. Prevent propagation of thermal runaway
4. Redundant monitoring & protection
5. Physically protect the battery pack
6. Extensive testing and validation
5. Physically protect the battery packRoadster wrecked at 100kph
Tesla Approach to Battery Safety/Reliability
1. Start with a safe, reliable cell
2. Prevent thermal runaway
3. Prevent propagation of thermal runaway
4. Redundant monitoring & protection
5. Physically protect the battery pack
6. Extensive testing and validation
Cell Test Data Results
Approval received from DoT to ship Tesla 53kWh mass production battery pack by boat, truck or air.
6. Extensive Testing and Validation
Vibration Testing using USABC Test procedure #10 (same as SAE J2380)
6. Extensive Testing and ValidationPack level test
• Suggested test for “traction batteries hard mounted to a chassis of an EV”. • 38 hours simulate 100,000 miles of driving.
PAVE – 1K kmVehicle durability – 40K km
Each test equivalent to 100K miles driving
6. Extensive Testing and Validation
CorrosionSalt splash (part of 40,000km mixed durability)
76 times throughout testenter 30 km/hexit 55km/h
The ESS must be able to withstand the salt spray test specified in the Vehicle Technical Specification as well as SAEJ1211 sections 4.3 and ASTM B 117-73.
6. Extensive Testing and Validation
Tesla Roadmap
Tesla confirms smart EV battery supply deal
Posted Jan 13th 2009 by Sam Abuelsamid, AutoblogGreen“The rumors were true. At the Society of Automotive Analysts outlook conference this morning, Tesla CEO Elon Musk announced that his company will supply lithium ion battery packs and charging systems to Daimler AG. The components will be used to power the second-generation smart ed. Daimler will build 1,000 of the electric smarts for field testing beginning this year. Some of those will be coming to the US in 2010. Tesla and Daimler are collaborating on development of the batteries. Musk told ABG that the program began in November 2007 and the first prototype was ready in 40 days.”
Tesla Roadster250+ produced1,000+ reservations
OEM powertrains
Tesla Model SLuxury Sports SedanMarket intro: March 26thProduction starts: 2011
High performanceZero emissions200+ mile rangeProprietary technology
Foundation of Revolutionary Vehicles
100% Electric Powertrains
Leverages zero-emissions electric powertrain
In advanced development, production targeted for late 2011
Designed for exceptional performance, aesthetics and functionality– 7 passengers: 5 adults + two child seats
– 4 doors + hatchback Best in class cargo space
– All wheel drive options
– World class design; unrivaled user interface
Target Performance– 0-60 mph acceleration: 5.7s (standard), 4.4s (sport)
– EPA driving range: 160 miles, 230 miles, 300 miles
Advanced range capabilities– Usage of multiple advanced cell chemistries
– 45 minute charge capability
– 5 minute battery pack swap capability
Base price $49,900 after Federal Tax Credit
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